JPS6215817B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for correcting the output of an infrared sensing element, which corrects variations in the output of a plurality of infrared sensing elements.

2. Description of the Related Art Infrared imaging devices have been used to measure the temperature of the surface of an object. This infrared imaging device is
The purpose is to determine the temperature distribution on the surface of an object by measuring the intensity of infrared rays radiated from the object.

Such an infrared imaging device has a plurality of detection elements DET ₁ to _{DET 4} arranged diagonally as shown in FIG.
By moving the scanning line by 4 elements,
I am trying to scan one screen. In this case, if the output voltage fluctuates due to variations in the characteristics of each sensing element, the thermal pattern cannot be accurately displayed.

The present invention has been made in view of these points, and aims to automatically correct the output voltage of each element to display a uniform thermal pattern. Each of the outputs of a plurality of infrared detection elements is held, and the difference between the outputs of the plurality of infrared detection elements and the remaining outputs is determined as a reference, and this difference is determined multiple times, averaged, and stored in memory, and during operation. , by an output correction method of a multi-element infrared detector, in which the difference in the memory is added to the remaining outputs of the plurality of infrared detection elements excluding the output of the element used as a reference, and the output is output. achieved.

The present invention will be explained below based on examples. Second
The figure shows an embodiment of the present invention, and FIG. 3 is an explanatory characteristic diagram of a linearizer. In the figure, AM ₁ to _{AM 4}
is an integrated amplifier, CL ₁ to _{CL 4} are clamp circuits, AS is an analog switch, BA is a buffer amplifier, SH is a sample hold circuit, A/D is an analog-to-digital exchanger, R ₁ is a register, OP is an arithmetic circuit, M ₁ to M ₃ is memory, PRR is programmable read-only memory writer, PR ₁ to _{PR 3} is programmable read-only memory, DS is data selector, ADD is adder circuit, PT1, PT2 are printed board, TA, TB are timing generator, SCN is the horizontal scanning drive section, TC is the calibration timing generation section, BD
is a blackbody furnace.

In the present invention, when calibrating the detection elements DET ₁ to _{DET 4} , the printed board PT1 is inserted into the device and the programmable read-only memory
Write the correction values to PR ₁ to _{PR 3} , insert the printed board PT2 on which the read-only memory PR ₁ to PR ₃ with the correction values written during operation into the device instead of the printed board PT1, and make corrections using the correction values. and output it.

The writing of the correction value and the operation of correction using the correction value will be explained below. First, during calibration, the infrared detection elements DET ₁ to _{DET 4} are guided from the blackbody furnace BD. Detection element
The output of DET ₁ ~ _{DET 4} is the integrated amplifier AM ₁ ~
Amplified by AM ₄ and clamp circuit CL ₁ ~
Enter CL ₄ . Clamp circuits CL ₁ to _{CL 4} are based on the drive signal from the horizontal drive circuit SCN of the scanning mirror, synchronized with the clock signal created by the timing generator TA, and set the output voltage based on the infrared rays from the blackbody furnace BD as a reference. and clamp it. The outputs of clamp circuits CL ₁ to _{CL 4} are analog switches.
It is multiplexed by AS and input to the sampling hold circuit SH via the buffer amplifier BA. The sampling and holding circuit SH samples and holds the input analog signal and inputs it to the analog-to-digital converter A/D. The analog/digital converter A/D converts the sampled value into AD. If the output of the detection element DET ₁ is used as a reference here, the output of the detection element DET ₁ is sampled, the A/D converted output value is input to the register R ₁ , and the output value of the other detection element DET 1 is input to the DET ₄ of the other detection element DET ₁ . The arithmetic circuit OP calculates the difference between the output and the value in the register _R1 , and sequentially adds this difference to the areas A of the memories _M1 to _M3 . (The number of additions is also stored at the same time.) At this time, A/D converted signals are used as address signals for the memories M ₁ , M ₂ , and M ₃ . The above steps are repeated while changing the temperature of the blackbody furnace BD from room temperature to high temperature and from room temperature to low temperature using the control unit PCON. As a result, the total sum of differences due to variations in elements is stored from address 0 to the final address of memories M ₁ to M ₃ .

The storage timing in the memories _M1 to _M3 is as follows: When the sweep of the temperature of the blackbody furnace, which is performed in synchronization with the timing signal from the calibration timing generator CT, is completed, the next memory is stored in the arithmetic circuit OP for each address from 0 to the final address. Perform the calculation to find the average value.

Total sum of difference values/number of additions This calculation result is stored in area B of memories _M1 to _M3 . Next, the value of area B is stored in the programmable read-only memories PR ₁ to _{PR 3} by the programmable read-only memory writer PRR. When operating the infrared detection device, programmable read-only memories PR ₁ to _{PR 3} are connected to printed board PT _2.
and insert it into the device instead of printed board PT ₁ . Of the signals output from the analog-to-digital converter AD, the output from the detection element DET ₁ is sent to the display unit via the data selector DS and linearizer LA ₁ so that the relationship between temperature and output voltage becomes a straight line. input.

Next, regarding the outputs of the detection elements DET ₂ , DET ₃ , and DET ₄ , the output of the analog-to-digital converter A/D is input to the adder circuit ADD, and is also input as an address signal to the programmable read-only memories PR ₁ to _{PR 3} . do. As a result, the correction values at each temperature are output from the programmable read-only memories PR ₁ to _{PR 3} , added by the adder circuit ADD, and sent to the linearizer via the data selector DS.
Enter LA ₂ . As a result, the output of the sensing element is corrected and input to the display section.

As described above, according to the present invention, the output of each detection element can be automatically corrected and output, and a uniform thermal pattern can be displayed.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the arrangement of sensing elements, and FIG. 2 is a diagram showing an embodiment of the present invention. In the figure, DET ₁ to _{DET 4} are detection elements, AM ₁ to _{AM 4} are integrated amplifiers, CL ₁ to _{CL 4} are clamp circuits,
AS is an analog switch, BA is a buffer amplifier,
SH is a sampling hold circuit, A/D is an analog-to-digital converter, _R1 is a register, OP is an arithmetic circuit, _M1 to _M3 are memories, PRR is a programmable read-only memory titer, and _PR1 to _PR3 are programmable reads. Only memory, ADD is an adder circuit, and DS is a data selector.

Claims (1)

[Claims] 1. During calibration, each output of a plurality of infrared detection elements is held, and one of the outputs of the plurality of infrared detection elements is used as a reference to determine the difference between the outputs of the remaining outputs, and this difference is determined multiple times, averaged, and stored in memory. A method for correcting the output of a multi-element infrared sensing element, in which the difference in the memory is added to the remaining outputs of the plurality of infrared sensing elements excluding the output of the element used as a reference during operation, and the output is output. .